Elastic strand for incorporation into elastic fabrics



s. c. LILLEY 2,146,965

v ELASTIC STRAND FOR INCORPORATION INTO ELASTIC FABRICS Feb. 14, 1939.-

Filed July 22, 1957 40 I which may be applied to the strands or. impairing the appearance ofthe fabric in which the strands Patented Feb. 14, 1939 PATENT OFFICE ELASTIC STRAND FOB INCORPORATION INTO ELASTIC FABRICS Samuel C. Lilley, Hamden, Conn assignor to The American Mills Company, New Haven, Conn.,

a corporation of Connecticut Application July 22, 1937, Serial No. 154,962 '1 Claims. (CL n This invention relates-to an improvement in.

elastic strands for incorporation into elastic fabrics, and more particularly to an improved elastic strand for the purpose referred to, which 5 elastic strands are provided with a localized coating of heat-soft'enable adhesive-forming mate.- rial, by which the elastic strands may be anchored to a covering material or to the cross-strands of a fabric in which the elastic strands are incorporated. r

I The present invention, as will be apparent from the following, contemplates an elastic strand of rectangular form in cross-section and designed for incorporation into elastic fabrics and having one or more of its angularly-related faces provided with a longitudinally-extending coating or area of heat-softenable adhesive-forming thermoplastic material which is capable of being rendered actively adhesive by heat, so that covering 0 material or cross-strands of a fabric may be anchored to the elastic strands.

One of the objects of the present invention is to provide a superior elastic strand having a lo- ,calized area or coating of heat-softenable adhesive-forming material fixedly united therewith. A further object is to provide a superior elastic strand of the character above referred to, which is economical to produce and convenient to use. Another object of the present invention is to provide a superior elastic strand which includes heat-softenable or thermo-plastic adhesive-forming material and which will not mar the appearance of covering material applied thereto nor similarly affect fabrics in which the strand is inf corporated. A still further object of the presentin'vention is to provide a superior elastic strand for incorporation into elastic fabrics, and having an adhesive-forming coating so located that an excess thereof is guarded against to thus avoid impairing the appearance of covering material may be incorporated.

Another. object of the present invention is to provide a superior elastic strand which includes heat-softenable or thermo-plastic adhesive-forming. material and which will not mar the appeara separate application.-

In the accompanying drawing! i Fig. 1 is a broken schematic perspective view 60 illustrating a mode of applying thermo-plastic adhesive-forming layers or coatings to the respective opposite faces of a sheet of elastic body-material;

Fig. 2 is a broken face view of the sheet mate rial shown in Fig. 1 after the same has been coated 5 and has been partially slitted to produce. a pin-- rality of individual elastic strands of rectangular form in cross-section;

Fig. 3 is a perspective view on an enlarged scale of a section of elastic strand out from the sheet 10 Fig. 4 is a broken view in side elevation showing the strand of Fig. 3 with a helical wrapping of covering strand material applied and-thermoplastically adhered thereto;

Fig. 5 is a broken longitudinal sectional view thereof taken on the line 5-5 of Fig. 6, but 'on a' greatly-enlarged scale; I

Fig. 6 is a transverse sectional view taken on' the line 66 of Fig. 4 and also shown on a greatlyenlarged scale: and V Fig. '7 is a perspective view of another form of elastic strand embodying the present invention. The particular elastic strand herein chosen for the illustration of the present invention in the 2 figures includingand preceding Fig. 6, is generally designated by the reference character [0, and includes a body ll of elastic material and layers or coatings i2 and i3 fixedly secured to two-of its respective opposite faces, as is especially well shown in Fig. 3.

-.The elastic bodies ll above referred to, may be made of a variety ofelastic materials, such, for instance, as the vulcanized rubber compounds common in the textile art, and preferably having 5 a heat-softening or disintegrating point mate! rially above the temperature at which the thermoplastic adhesive-forming material l2 and I3 used in conjunction with the body II, will effectively soften.

. In addition to the usual and other elastic compounds, in the textile art, the following compound may be mentioned as particularly suitable for the production of elastic body-strands when cured for about forty-five minutes at approximately two hundred sixtydegrees Fahrenheit:

i Parts 1 by weight Rubber 100 Sulphur stearic acid 1 Symmetrical di-beta-naphthyl-para-phenylenediamine 1 Zinc sulphide 5 Phenylhydrazine ,5 V zinc salt of mercaptobenzothiazole} 1 10% di-ortho-tolylguanidine Zinc oxide 5 Methylacrylic ester 20 o The material from which the thermo-plastic adhesive-forming material may be constituted, in accordance with the'present invention, may vary widely, but preferably, should embody all of the- (d) Characteristics which will not deleterious- 1y affect either the covering material or the elastic core-strand.-

The following examples of thermo-plastic adhesive-forming materials are given by way of iilustration: I

Example A Parts by weight Blended rubber (para and/or pale crepe) Zinc mridp v 5 Zinc sulphid 5 Stearic acid 3 Sulphur /2 Mercaptobenzothiazole 1 .Sym. di-beta-naphthyl-para -phenylenediamine 1 Example B Rubber 100 Dibutyl-ammonium-oleate-.. a 3

Example. 0

Rubber 100 Meta-.toluelene-diamine 1 Example D Rubber 100 Dl-penta -methylene-thiuram tetra sul phide v 3 Q Example E Balata.

. v Example F Methyl-polyacrylate.

' Example G Gutta-percha. Example H Rubber 100 Fatty anhydride (stearic acid-or the like)- 3 The rubber content in the above Examples A,

3,0 and D, shduld preferably be what is known in the trade as pure rubber mix which is mehanically worked at high temperatures to produce a tough product with a minimum breakdown of the rubber itself. The pure rubber hy-- comes rulcanized or set at about 220 degrees F.,

and is not again softenable except at temperatures very materially beyond those encountered in any normal use to which elastic fabrics would be put.

In producing the elastic strands of the present invention, a body-sheet I 4 of previously-vulcanized elastic material may be passed between complemental sheeting-rolls I5 and I6, as is schematically illustrated in Fig. 1. The body-sheet I 4, before passing between the sheeting-rolls I5 and I6, should be thoroughly cleansed and freed of talc. Interposed between the sheeting-roll I5 and the upper surface of the elastic body-sheet I4 is a very thin coating-sheet I! of thermoplastic adhesive-forming material which is preferably about .002 to about .003" thick and which is preferably pressed against the body-sheet I4 while in a tacky condition, so as to firmly adhere to the previously-cleaned surface of the said body-sheet and thus become to all intents and purposes a unitary part thereof.

In a similar manner, a coating-sheet l8 of the same general character as the coating-sheet I I, is pressed against the under surface of the previously-cleansed body-sheet I4 by the lower sheeting-roll I6, so as also to become in effect an integral part of the said body-sheet I4. 3

The now-completed sheet, which includes the parts I4, I1 and I8, is now passed through a suitable slitting machine (common in the art) so as to be cut into a plurality of strands III. The layers or coating-sheets I2 and I3, as will be obvious from the foregoing, may be aptly designated as potential adhesive-forming material, inasmuch as the said material is but a potential adhesive which will become fully efiective only when subjected to heat.

The strand III, in its naked condition, may now be woven, knitted or otherwise incorporated into a fabric, and after the fabric has been completed, the same may be heated to convert the potential adhesive-forming material I2 and I3 into an active adhesive which will serve to anchor the strand Ill to the cross-threads of the fabric, so that in the event that a given elastic strand should become severed, it will not creep back in'the fabric to a harmful degree owing to its being anchored to the strands thereof.

For many of the high-class elastic fabrics, it is desirable to provide the elastic strands with a covering. material which will serve to conceal the elastic strand itself. In applying covering material to the elastic strand III, the said strand is preferably partly stretched, and while in this condition, one or more covering-strands I9 of "suitable textile material are helically wrapped instance, as cotton, wool, silk, regenerated cellulose, etc.

The tension at which the covering-strands l9 are applied to the strands IIl is preferably sufllcient to press in the four corners of the rectangular strand Ill into substantially the form shown in Fig. 6. The elastic strand II) as thus covered may now be subjected to the action of heat (either before or after its incorporation into'a fabric), which heat will render the layers I2 and I3 sufficiently soft or tacky to adhere the coveringstrands III or their equivalent, to the elastic body II, as is schematically illustrated in Fig. 6.

It is exceedingly difficult to insure a sumciently-thin coating of adhesive-forming mate rial upon the body II of an elastic strand, without resorting-to relatively-thick coatings of such adhesive material l2 and I3. n h s been found,

of the body ll bare, the coatings may be of such appreciable thickness as to be convenient to apply without the likelihood of their deleteriously affecting the appearance of the covering material or of the fabric, when heated.

By so applying the thermo-plastic adhesiveforming material to the body II that certain portions of the said body ll are-left bare of such adhesive material, the danger of discoloring or otherwise harmfully affecting the appearance of the covering material, or of the fabric in which the strand I0 is incorporated, is reduced to a minimum, since to some extent the layers l2 and I3 will flow around the uncovered faces of the body II and thus reduce the amount of adhesive-forming material on the opposed faces of the body II, as initially covered or coated with the said adhesive-forming material.

If desired, and as shown in Fig. 7,' an elastic body 20 may be employed which is'provided on its respective opposite faces with transverse an- 'choring-grooves 2| which may be produced by pressing the material of which the body 20 is formed between sheets of fabric having promierably before the curing or vulcanizing of the elastic material of which the body 20 is formed. Suitably applied to one of the grooved faces 2| of the body 20 is a layer or sheet 22 (preferably about .0045" thick) of thermo-plastic adhesiveforming material which is to thoroughly united with the said body 20- as to virtually be apart thereof.

When the strand 23 of Fig. '7 is provided with helically-applied covering-strands or is incorporated in the naked condition into a fabric, the transverse anchoring-grooves 2| will serve to minimize the slippage of the strandswith respect to the material of the fabric or the covering strands wrapped about them. s

It will be seen from the foregoing that by means of the present invention an elastic strand having thermo-plastic adhesive-forming material, is provided which does not require that the said adhesive-forming material be almost .im--

palpably thin in order to avoid an excess thereof which might deleteriously affect the appearance of the coveringmaterial lor the'strands of the fabric in which the elastic strand is incorporated.

In covering elastic strands, it is customary to wind numerous parallel strands upon a single reel, and in the event that it should be found under any given set of conditions thatthe adhesive-forming coating of the strands of the present invention, prior to covering, are apt to adhere to each other, such adhesion may be remedied in various ways. For instance, the

coated strands, before being wound upon the reel with companion strands, may be passed through a bath of water-soluble gum combined with talc. A suitable gum for this purpose is locust bean gum. Another 'mode of overcoming any tendency of the unvulcanized rubber coatings of elastic strands to stick together, prior to their being covered, comprises passing the strands through a dilute vapor of sulphur chloride and carbon tetrachloride, which will efiect only a slight surface or skin cure of the unvulcanized rubber coating.

The invention may be carried out in other specific ways than those herein set forth without The anwoven or knitted into elastic fabrics, comprising: 10

an elastic strand-body of rectangular form in cross-section; and acoa'ting of thermoplastic adhesive-forming material fixedly united to at least one of the angularly-related faces of the said elastic strand-body; certain of the angularlyrelated faces of thesaid elastic strand-body being free of said thermo-plastic adhesive-forming material to thereby, minimize the undue exudation of the said thermo-plastic adhesive-forming material between covering strands or the like when 20 the latter is applied to the elastic strand.

2. An elastic strand of the type adapted to be woven or knitted into elastic fabrics, comprising: an elastic strand-body of rectangular form in cross-section; and a coating of thermo-plastic adhesive-forming material fixedly united to only one of the four angularly-related faces of the said rectangular elastic strand-body; three of the four angularly-related faces of the said rectangular elastic strand-body being free of the said thermo-plastic adhesive-forming material to thereby minimize the undue-exudation of the said thermo-plastic adhesive-forming material between covering strands or the like when the latter is applied to the elastic strand.

3. An elastic strand of the type adapted to be woven or knitted into elastic fabrics, comprising: an elastic strand-body of rectangular form in cross-section; and a coating of thermo-plastic adhesive-forming material fixedly united to two alternate and opposed faces of the said rectangular elastic strand-body; the remaining two alternate and opposed faces of the said strand-body being free of such thermo-plastiE adhesive-formterial fixedly united to at least one of the angularly-related faces of the said elastic strandbody; certain of the angularly-related faces of the said elastic strand-body being free ofsuch thermo-plastic adhesive-forming material to thereby minimize the undue exudation of the said thermo-plastic adhesive-forming material between covering strands or the like when the latter is applied to the elastic strand; the said elastic water-insoluble thermo-plastic adhesiveforming material having an effective softening 6 point at a temperature above the boiling point of water and below the heat-disintegrating temperature of the said elastic strand-body.

5. A covered elastic strand of the type adaptedto be woven or knitted into elastic fabrics, com- 7 prising: an elastic strand-body of rectangular form in cross-section; an elastic water-insoluble thermo-plastic adhesive-forming material fixedly united to atleast one of the -angularly-relatedfaces of the said rectangular strand-body; certain of the other angularly-related faces of the said strand-body being freeof such thermoplastic adhesive-forming material; and covering material in strand form hellcally applied around the said strand-body and the localized adhesiveforming material thereon and bonded to the said strand-body by the latter.

6. An elastic strand of the type adapted to be woven or knitted into elastic fabrics, comprising: an elastic strand-body; a coating of thermoplastic adhesive-forming material flxedly united to a longitudinally-extending zone covering but portion of the perimeter of the said elastic strand-body to thus leave a longitudinally-extending zone on a portion of the said elastic strand-body relatively free of such thermo-plastic adhesive-forming material to thereby minimize the undue exudation oi! the said thermo-plastic adhesive-forming material between covering strands or the like when the latter is applied thereto.

7. An elastic strand of the type adapted to be woven or knitted into elastic fabrics, comprising:

- an elastic strand-body;- a coating of adhesive material adhered to a longitudinally-extending zone covering but a portion of the perimeter of the said elastic strand-body to thus leave a longitudinally-extending zone on a portion of .the said -elastic strand-body relatively free of such adhesive material to thereby minimize the undue exudation of the said adhesive material between covering strands or the like when the latter is applied thereto.

' SAMUEL C. LILLEY. 

